Duane Knudson - Biomechanical Principles of Tennis Technique: Using Science to Improve Your Strokes

Copyright 2006 by Duane Knudson

Racquet Tech Publishing

(An imprint of the USRSA)

330 Main St.

Vista, California 92084

www.racquettech.com

All rights reserved. No portion of this publication may be reproduced, stored in a data retrieval system, or exhibited, displayed or transmitted in any form or by any means, whether digital, electronic, mechanical, photocopying, recording or otherwise, without the express written consent of the publisher.

Library of Congress Control Number: 2005938186

Cover design and illustrations by Kristine Thom

Photos courtesy of USTA High Performance and the International Tennis Federation (ITF)

Printed in the United States of America

ISBN-13: 978-0-9722759-4-1

ISBN-10: 0-9722759-4-0

CONTENTS

The purpose of this book is to give tennis players knowledge of key concepts of biomechanics so they can make informed decisions about stroke techniques. Tennis players naturally want to maximize performance while minimizing the risk of injury. These are also the two primary goals of research in sport biomechanics.

The book is not intended to replace your tennis pro. Most certified tennis professionals have some training in the application of biomechanics to tennis strokes. This book will help you interact with your pro/coach to make wise decisions about adjustments to your game. Tennis pros will likely help you integrate the information in this book with the strategic (match plan) and tactical (specific implementation of strategy) knowledge this book does not cover. This book will also help tennis pros and coaches update their knowledge on the mechanics of strokes. Reference citations are provided for key papers, sources, and as tips to readers interested in additional information. I encourage all readers to explore these excellent sources. I apologize to some of my peers whose work could also be cited to support many points, but all supporting data would be a distraction to most readers.

Considerable research has been done on tennis strokes and other striking sports that allows for the creation of a few general principles of tennis mechanics. Tennis mechanics includes the biomechanics of stroke production and the mechanics of ball flight. This book is your introduction to these principles. On the way I will discuss examples of how you apply these principles in an injury prevention program and improving your strokes. There will also be integration boxes because biomechanical knowledge should not be applied separate from the context of the performer, task, or situation. Integration, Advantage, and Stroke Technique boxes provide links to how biomechanics can be integrated with other sport sciences or factors to improve our understanding of the game. Lets get started!

I would like to thank Crawford Lindsey and Kristine Thom of Racquet Tech Publishing and the United States Racquet Stringers Association for their valuable contributions to the book. Some of the application boxes and nice features of this book are due to their fine suggestions. There are also many tennis scientists, coaches, and physicians who have been very generous in sharing their data and expertise with me. Space does not allow me the opportunity to thank all of them individually, but they have my sincere gratitude.

A common trait of recreational players is that they try to do things with their hands to make up for their lack of quickness and positioning with their feet as they hit the ball. - Arthur Ashe

A ny meaningful discussion of variations of tennis stroke technique requires knowledge of sport biomechanics. Biomechanics is the field of study that focuses on understanding the motion and causes of motion of living things. Sport biomechanics, naturally, focuses on how humans create a wide variety of movements in sports. Fortunately for the tennis player and coach, there is a large body of research on the biomechanics of tennis movements. From the footwork to move on the court, to the adjustments in the stroke to create topspin, biomechanics is an essential tool for understanding movement in tennis.

This text will not revel in the details of this research and its limitations, but will be concerned with painting a picture of the consensus of this body of knowledge that can be applied to tennis. It is easy for biomechanical analyses to churn out hundreds of thousands of numbers representing the time varying values of a myriad of force and motion variables. What is more important, and more difficult, is the identification of key variables that are most influential and interpreting how they affect performance or injury risk. (See for a brief discussion of the differences between the levels of scientific evidence and coaching opinion.) Often the biomechanical research supports the experiential wisdom of tennis coaches, but at times the research points to interesting and counterintuitive ideas. This is not surprising given the complex mechanical properties of biological tissues, the complexity of the musculoskeletal system, and the high-speeds of the game that make most aspects of the movements truly invisible to the naked eye.